In recent years, aviation headsets have expanded in functionality from being two-way communications headsets meant only for use with an aviation intercom system (ICS) to additionally including the ability to accept (wirelessly or via conductive cabling) audio from an auxiliary audio source to (e.g., a tape recorder playing music, solid-state music playing device, etc.), to provide active noise reduction functionality (ANR), and to wirelessly link with cell phones for two-way communications with that cell phone. However, the addition of these newer functions to an aviation headset imposes a requirement that electric power be provided to that headset.
Unfortunately, predominant aviation headset interface standards employed in coupling a headset to an ICS in many forms of aircraft were never meant to supply a headset with electric power. The “general aviation” (GA) interface, which is the most widely used form of aviation headset interface standard in civilian airplanes, employs a pair of connectors that enable the connection of two microphone conductors and a push-to-talk (PTT) control conductor through one of the connectors, and the connection of left and right audio channel conductors and an associated ground conductor through the other of the connectors. Correspondingly, the most widely used form of aviation headset interface standard in helicopters employs a single connector, the “U-174” connector, that enables the connection of two microphone conductors and only a monaural audio channel conductor and associated ground conductor. These interface standards were created at a time in which carbon microphones requiring a relatively high 8-16V microphone bias voltage were used, and provision of this relatively high bias voltage continues to the present day despite the vast majority of currently used headsets incorporating either an electret microphone needing only a much smaller bias voltage or a dynamic microphone needing none. Unfortunately, this relatively high bias voltage is typically provided with relatively small current capacity, making it unsuited for use in powering such newer functionality due to the likelihood of generating distortion in the signal output by the microphone.
An alternative aviation headset interface employing a single six-pin connector that replaces the PTT conductor with a power conductor to convey 8-32V with greater current capacity to a headset has been introduced in recent years, commonly referred to as a “Lemo” interface in reference to the original manufacturer of the six-pin connector it uses, i.e., LEMO® of Switzerland. Unfortunately, despite the introduction of the “Lemo” interface, the GA and U-174 interfaces remain the predominant ones used in civilian airplanes and in helicopters, respectively. As a result, aviation headsets must frequently support carrying relatively large capacity batteries to support the newer functionality, resulting in an undesirably bulky and heavy control box positioned along a cable of a headset to hold those batteries, which must be replaced from time to time.